Morning Sickness

[MacXC60T5]

Had my V70T5 2001 39000 mls serviced a few days ago, every thing was running ok. when I got my car back the following morning when started it ran very rough for a few minutes its like its not firing correctely and no excelleration untill it sorted itself out it then runs ok. I took the car back to the garage for a test and sure enough there was no problem, so, there is only a problem in the morning or when its been standing for a few hours. This is my fifth Volvo and the first time I have ever had this problem.
Has anybody had a similar problem or can anybody offer me advice. As a general note I posted a topic for V70T5 Oil. I discovered that my vehicle has only had semi and not fully synth. Other than this small problem I am very pleased with my T5. I know its not a major problem but its a pain in the ar-s.
Any help would be appreciated.